One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,9)(8,10)(11,12)(13,14,18,21)(15,22,24,28)(16,20,17,26)(19,27,23,25)(5,6)(7,11)(8,10)(9,12)(13,15)(14,19)(16,25)(17,27)(18,24)(20,28)(21,23)(22,26) involution — undirected(2,4)(5,7,8,12)(6,9,10,11)(13,14)(15,23)(16,26)(17,20)(18,21)(19,24)(22,27)(25,28)(7,12)(9,11)(13,16)(14,20)(15,24)(17,18)(21,26)(22,28) involution — undirected(6,10)(9,11)(14,21)(19,23)(20,26)(22,28) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.